Topical hypochlorite ameliorates NF-κB-mediated skin diseases in mice

Myeloperoxidase induces monocyte migration and activation after acute myocardial infarction

Introduction

Myocardial infarction (MI) is a significant contributor to morbidity and mortality worldwide. Many individuals who survive the acute event continue to experience heart failure (HF), with inflammatory and healing processes post-MI playing a pivotal role. Polymorphonuclear neutrophils (PMN) and monocytes infiltrate the infarcted area, where PMN release high amounts of the heme enzyme myeloperoxidase (MPO). MPO has numerous inflammatory properties and MPO plasma levels are correlated with prognosis and severity of MI. While studies have focused on MPO inhibition and controlling PMN infiltration into the infarcted tissue, less is known on MPO's role in monocyte function.

Methods and results

Here, we combined human data with mouse and cell studies to examine the role of MPO on monocyte activation and migration. We revealed a correlation between plasma MPO levels and monocyte activation in a patient study. Using a mouse model of MI, we demonstrated that MPO deficiency led to an increase in splenic monocytes and a decrease in cardiac monocytes compared to wildtype mice (WT). In vitro studies further showed that MPO induces monocyte migration, with upregulation of the chemokine receptor CCR2 and upregulation of inflammatory pathways identified as underlying mechanisms.

Conclusion

Taken together, we identify MPO as a pro-inflammatory mediator of splenic monocyte recruitment and activation post-MI and provide mechanistic insight for novel therapeutic strategies after ischemic injury.

Tolerability and the effect on skin Staphylococcus pseudintermedius density of repeated diluted sodium hypochlorite (bleach) baths at 0.005% in healthy dogs

BACKGROUND

Dilute sodium hypochlorite (bleach) baths at 0.005% concentration twice weekly have been shown to markedly reduce the severity of atopic dermatitis in children, yet no tolerability and efficacy data are available for this treatment in dogs.

OBJECTIVES

To determine the local tolerability and the longitudinal effect on the density of Staphylococcus pseudintermedius of repeated diluted bleach baths on healthy dog skin.

ANIMALS

Four healthy hound cross-bred dogs.

METHODS

Bleach baths (0.005%; twice weekly for 15 min) were applied to four healthy hound cross-bred dogs over four weeks (eight baths). Local tolerability was assessed for axillae, abdomen and legs by an investigator before, immediately after and 24 h after each bath. The longitudinal effect on density of S. pseudintermedius from axillae and groin was analysed through quantitative PCR before treatment [at Day (D)-7 and -3], during treatment on D4, D11 and D25, and on D30.

RESULTS

There was no erythema or scaling after the baths in any dog. Copy numbers of S. pseudintermedius in axillae, groin and both (axillae and groin together) were not significantly different at any time point during the study.

CONCLUSIONS AND CLINICAL RELEVANCE

Repeated 0.005% hypochlorite bleach baths over four weeks were safe and well-tolerated in healthy dogs without significant changes in the density of S. pseudintermedius.

Bleach baths enhance skin barrier, reduce itch but do not normalize skin dysbiosis in atopic dermatitis

Studies have demonstrated that bleach baths improve atopic dermatitis (AD) severity; however, the effects on itch, skin barrier, and cutaneous microbial composition are less clear. We examined whether bleach baths reduce itch, normalize skin barrier function, reduce S. aureus absolute abundance, and increase microbial diversity in adults with AD who were colonized with S. aureus on their non-lesional skin. This was an open label, non-randomized, controlled trial performed at a single academic center. Fifteen AD and five non-atopic healthy controls (NA) were instructed to take two bleach baths (0.005% NaClO; 5-10 min duration) per week for a total of 12 weeks as add-on therapy. Adults 18 to 65 years (inclusive) with mild to severe AD were recruited with EASI score > 6.0, S. aureus culture positivity, access to a bathtub, and ability and willingness to maintain current topical or systemic treatments. They were evaluated at baseline (before bleach baths), 6 weeks, and 12 weeks after the intervention of twice-weekly bleach baths. Efficacy measurements included EASI as well as 5-D Pruritus and ItchyQoL™. Transepidermal water loss (TEWL) and stratum corneum (SC) integrity assay were performed to assess the skin barrier. Skin dysbiosis was measured by S. aureus cultivation, S. aureus abundance (qPCR of thermonuclease gene), and V1-V3 16S rRNA gene sequencing on non-lesional and lesional AD skin. After 12 weeks of bleach baths, 8/15 (53.3%) AD subjects achieved an EASI50 and a significant reduction in itch as measured by 5-D pruritus and Itchy QoL. Eighty-seven percent reported improvements in sleep quality. At study entry, AD subjects had higher non-lesional TEWL values than NA subjects, and only AD subjects experienced a reduction with bleach baths (p = 0.006). Similarly, SC integrity improved as early as 6 weeks after bleach baths in AD subjects. Notably, bleach baths had no significant effect on S. aureus culture-positivity, qPCR absolute abundance, or microbial diversity. The addition of twice-weekly bleach baths improves investigator-assessed AD severity, patient-reported pruritus and sleep as well as physiological measures of skin barrier function in adult AD subjects while having no effect on qualitative and quantitative measures of cutaneous S. aureus. Trial Registration: ClinicalTrials.gov Identifier: NCT01996150, Date of registration: November 27th, 2013.

The Drinking Water and Swimming Pool Disinfectant Trichloroisocyanuric Acid Causes Chlorination Stress Enhancing Solar UV-Induced Inflammatory Gene Expression in AP-1 Transgenic SKH-1 Luciferase Reporter Mouse Skin

Freshwater sanitation and disinfection using a variety of chemical entities as chlorination agents is an essential public health intervention ensuring water safety for populations at a global scale. Recently, we have published our observation that the small molecule oxidant, innate immune factor and chlorination agent HOCl antagonize inflammation and photocarcinogenesis in murine skin exposed topically to environmentally relevant concentrations of HOCl. Chlorinated isocyanuric acid derivatives (including the chloramines trichloroisocyanuric acid [TCIC] and dichloroisocyanuric acid [DCIC]) are used worldwide as alternate chlorination agents serving as HOCl precursor and stabilizer compounds ensuring sustained release in aqueous environments including public water systems, recreational pools and residential hot tubs. Here, for the first time, we have examined the cutaneous TCIC-induced transcriptional stress response (in both an organotypic epidermal model and in AP-1 luciferase reporter SKH-1 mouse skin), also examining molecular consequences of subsequent treatment with solar ultraviolet (UV) radiation. Taken together, our findings indicate that cutaneous delivery of TCIC significantly enhances UV-induced inflammation (as profiled at the gene expression level), suggesting a heretofore unrecognized potential to exacerbate UV-induced functional and structural cutaneous changes. These observations deserve further molecular investigations in the context of TCIC-based freshwater disinfection with health implications for populations worldwide.

Skin Antiseptics for Atopic Dermatitis: Dissecting Facts From Fiction

Staphylococcus aureus is a known trigger and cause of infectious complications in atopic dermatitis (AD). Various antiseptics have been used in an attempt to decrease the burden of S. aureus in AD. In this Commentary, we present the evidence for and against some of the commonly used antiseptics in clinical and research settings. These agents remain attractive as an adjunct therapy for AD owing to their relative low cost and potential benefits of reducing S. aureus. Although a number of studies have evaluated the use of dilute bleach, its mechanisms remain controversial. A higher concentration of bleach than the commonly used 0.005% is likely needed for its anti-S. aureus effect. Silver-coated textiles have demonstrated anti-S. aureus effects in various studies; however, their efficacy and side effects in AD remain to be confirmed. Other antiseptics including chlorhexidine, triclosan, and triclocarban are also discussed. Variables that may affect the outcomes of these studies include length of use, concurrent application of moisturizers, and anti-inflammatory medications.

Trichloroisocyanuric Acid (TCIC), A Swimming Pool Disinfectant: New Developments and Role in UV-Induced Skin Inflammation

This article is a highlight of the paper by Snell et al. in the current issue of Photochemistry and Photobiology (Snell et al. Photochem. Photobiol. 2022). The authors utilized an organotypic human skin model as well as transgenic SKH-1 mice to determine the oxidative stress response induced by topical treatment of trichloroisocyanuric acid (TCIC), a common disinfectant used in swimming pool. Additionally, they determined molecular mechanisms associated with topical TCIC pre-treatment followed by ultraviolet (UV) radiation exposure. This work provides the first example that cutaneous delivery of TCIC significantly increases UV-induced skin inflammation, suggesting a previously unidentified potential of TCIC. If translatable to human skin, these findings could be important for human skin health implications.

Narrative review on the management of moderate-severe atopic dermatitis in pediatric age of the Italian Society of Pediatric Allergology and Immunology (SIAIP), of the Italian Society of Pediatric Dermatology (SIDerP) and of the Italian Society of Pediatrics (SIP)

Currently, there are a few detailed guidelines on the overall management of children and adolescents with moderate-severe atopic dermatitis. AD ​​is a complex disease presenting with different clinical phenotypes, which require an individualized and multidisciplinary approach. Therefore, appropriate interaction between primary care pediatricians, pediatric allergists, and pediatric dermatologists is crucial to finding the best management strategy. In this manuscript, members of the Italian Society of Pediatric Allergology and Immunology (SIAIP), the Italian Society of Pediatric Dermatology (SIDerP), and the Italian Society of Pediatrics (SIP) with expertise in the management of moderate-severe atopic dermatitis have reviewed the latest scientific evidence in the field. This narrative review aims to define a pathway to appropriately managing children and adolescents with moderate-severe atopic dermatitis.

Brevilin A Ameliorates Acute Lung Injury and Inflammation Through Inhibition of NF-κB Signaling via Targeting IKKα/β

Acute lung injury (ALI) is life-threatening disease characterized by uncontrolled inflammatory response. IKKα/β, the key kinases in the activation of NF-κB pathway, are implicated in inflammatory pulmonary injury, and represent attractive targets for ALI therapy. Brevilin A (BVA) is a sesquiterpene lactone from Centipeda minima, a Chinese herb used to treat inflammatory diseases. This study aims to investigate the inhibition of BVA on ALI, with focus on clarifying the molecular mechanisms involved in BVA-mediated anti-inflammatory activity in macrophages. Briefly, BVA significantly inhibited the production of NO and PGE₂ by suppressing iNOS and COX2 expression, and suppressed the mRNA expression of IL-1β, IL-6, and TNFα in LPS/IFNγ-stimulated RAW264.7 macrophages. The anti-inflammatory activity of BVA was further confirmed in LPS/IFNγ-stimulated BMDMs and TNFα/IFNγ-exposed RAW264.7 cells. In vivo, BVA effectively attenuated LPS-induced lung damage, inflammatory infiltration, and production of pro-inflammatory cytokines, including MPO, IL-1β, IL-6, TNFα, and PGE₂. Mechanistically, BVA could covalently bind to the cysteine 114 of IKKα/β, and effectively inhibiting the activity and function of IKKα/β, thereby resulting in the suppression of phosphorylation and degradation of IκBα and the subsequent activation of NF-κB signaling. Furthermore, pretreatment of DTT, a thiol ligand donor, significantly abolished BVA-mediated effects in LPS/IFNγ-stimulated RAW264.7 cells, suggesting the crucial role of the electrophilic α, β-unsaturated ketone of BVA on its anti-inflammatory activity. These results suggest that BVA ameliorates ALI through inhibition of NF-κB signaling via covalently targeting IKKα/β, raising the possibility that BVA could be effective in the treatment of ALI and other diseases harboring aberrant NF-κB signaling.

Bleach baths for atopic dermatitis: A systematic review and meta-analysis including unpublished data, Bayesian interpretation, and GRADE

BACKGROUND

Bleach bathing is frequently recommended to treat atopic dermatitis (AD), but its efficacy and safety are uncertain.

OBJECTIVE

To systematically synthesize randomized controlled trials (RCTs) addressing bleach baths for AD.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and GREAT from inception to December 29, 2021, for RCTs assigning patients with AD to bleach vs no bleach baths. Paired reviewers independently and in duplicate screened records, extracted data, and assessed risk of bias (Cochrane version 2) and GRADE quality of evidence. We obtained unpublished data, harmonized individual patient data and did Frequentist and Bayesian random-effects meta-analyses.

RESULTS

There were 10 RCTs that enrolled 307 participants (median of mean age 7.2 years, Eczema Area Severity Index baseline mean of means 27.57 [median SD, 10.74]) for a median of 6 weeks (range, 4-10). We confirmed that other trials registered globally were terminated. Bleach baths probably improve AD severity (22% vs 32% improved Eczema Area Severity Index by 50% [ratio of means 0.78, 95% credible interval 0.59-0.99]; moderate certainty) and may slightly reduce skin Staphylococcal aureus colonization (risk ratio, 0.89 [95% confidence interval, 0.73-1.09]; low certainty). Adverse events, mostly dry skin and irritation, along with itch, patient-reported disease severity, sleep quality, quality of life, and risk of AD flares were not clearly different between groups and of low to very low certainty.

CONCLUSION

In patients with moderate-to-severe AD, bleach baths probably improve clinician-reported severity by a relative 22%. One in 10 will likely improve severity by 50%. Changes in other patient-important outcomes are uncertain. These findings support optimal eczema care and the need for additional large clinical trials.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42021238486.

Optimizing topical management of atopic dermatitis

OBJECTIVE

Provide a review of atopic dermatitis management, focusing on optimizing topical therapy, creating a stepwise approach for treatment plans, and providing guidance on when to start systemic therapy.

DATA SOURCES

PubMed search of articles in the English language regarding atopic dermatitis in all ages.

STUDY SELECTION

Articles on the subject matter were selected and reviewed.

RESULTS

Topical corticosteroids are the first-line treatment for managing atopic dermatitis. Topical nonsteroidal agents, calcineurin inhibitors, crisaborole, and recently, ruxolitinib, which cause no cutaneous atrophy, are options for reducing the use of topical corticosteroids, including on sensitive sites. Emerging topical agents are in clinical trials. Proactive management, with continued application 2 to 3 times weekly of a midpotency topical corticosteroid or tacrolimus, may maintain control for clear (or almost clear) localized sites of dermatitis that rapidly recur when topical anti-inflammatory medication is stopped. If topical therapy alone cannot control disease and quality of life is impacted, reevaluation to confirm the diagnosis, manage comorbid conditions, address compliance and patient-specific concerns, and optimize topical therapy must be undertaken before deciding to advance to systemic medication. Dupilumab, an interleukin-4 receptor inhibitor, has become first-line systemic therapy given its efficacy and safety, allowing long-term treatment without laboratory monitoring. Other biologics and Janus kinase inhibitors are emerging as alternatives that could eliminate the need for immunosuppressants with their higher risks.

CONCLUSION

Several options are now available for topical treatment. A stepwise approach is needed to consider alternative therapies and diagnoses before advancing to systemic treatment, but the safety of newer immunomodulators will lower the threshold for more aggressive intervention.

Hypochlorous Acid: From Innate Immune Factor and Environmental Toxicant to Chemopreventive Agent Targeting Solar UV-Induced Skin Cancer

A multitude of extrinsic environmental factors (referred to in their entirety as the 'skin exposome') impact structure and function of skin and its corresponding cellular components. The complex (i.e. additive, antagonistic, or synergistic) interactions between multiple extrinsic (exposome) and intrinsic (biological) factors are important determinants of skin health outcomes. Here, we review the role of hypochlorous acid (HOCl) as an emerging component of the skin exposome serving molecular functions as an innate immune factor, environmental toxicant, and topical chemopreventive agent targeting solar UV-induced skin cancer. HOCl [and its corresponding anion (OCl-; hypochlorite)], a weak halogen-based acid and powerful oxidant, serves two seemingly unrelated molecular roles: (i) as an innate immune factor [acting as a myeloperoxidase (MPO)-derived microbicidal factor] and (ii) as a chemical disinfectant used in freshwater processing on a global scale, both in the context of drinking water safety and recreational freshwater use. Physicochemical properties (including redox potential and photon absorptivity) determine chemical reactivity of HOCl towards select biochemical targets [i.e. proteins (e.g. IKK, GRP78, HSA, Keap1/NRF2), lipids, and nucleic acids], essential to its role in innate immunity, antimicrobial disinfection, and therapeutic anti-inflammatory use. Recent studies have explored the interaction between solar UV and HOCl-related environmental co-exposures identifying a heretofore unrecognized photo-chemopreventive activity of topical HOCl and chlorination stress that blocks tumorigenic inflammatory progression in UV-induced high-risk SKH-1 mouse skin, a finding with potential implications for the prevention of human nonmelanoma skin photocarcinogenesis.

The role of sodium hypochlorite in atopic dermatitis therapy: a narrative review

Atopic dermatitis (AD) is a common skin disorder, especially in the pediatric population. Genetic and immunological factors, epidermal barrier defect, as well as skin microbiota imbalance with increased colonization by Staphylococcus aureus (SA) are involved in the pathogenesis of the disease. One of the AD topical treatments is sodium hypochlorite (NaOCl) as a 0.005% water bath solution. This substance has been used for years as an antiseptic preparation. Studies show that NaOCl has an antimicrobial effect but probably at higher concentrations than those used in AD treatment. Nevertheless, many research studies confirm the anti-inflammatory and anti-itching effects of NaOCl, which contributes to clinical improvement in AD patients as well as reducing the need for local steroids and antibiotics. Bleach baths seem to be a well tolerated, cheap, and easily available therapy. However, research still should be continued to evaluate its antibacterial efficacy, anti-inflammatory effects, and safety.

NF-κB perturbation reveals unique immunomodulatory functions in Prx1+ fibroblasts that promote development of atopic dermatitis

Skin is composed of diverse cell populations that cooperatively maintain homeostasis. Up-regulation of the nuclear factor κB (NF-κB) pathway may lead to the development of chronic inflammatory disorders of the skin, but its role during the early events remains unclear. Through analysis of single-cell RNA sequencing data via iterative random forest leave one out prediction, an explainable artificial intelligence method, we identified an immunoregulatory role for a unique paired related homeobox-1 (Prx1)⁺ fibroblast subpopulation. Disruption of Ikkb-NF-κB under homeostatic conditions in these fibroblasts paradoxically induced skin inflammation due to the overexpression of C-C motif chemokine ligand 11 (CCL11; or eotaxin-1) characterized by eosinophil infiltration and a subsequent T_H2 immune response. Because the inflammatory phenotype resembled that seen in human atopic dermatitis (AD), we examined human AD skin samples and found that human AD fibroblasts also overexpressed CCL11 and that perturbation of Ikkb-NF-κB in primary human dermal fibroblasts up-regulated CCL11. Monoclonal antibody treatment against CCL11 was effective in reducing the eosinophilia and T_H2 inflammation in a mouse model. Together, the murine model and human AD specimens point to dysregulated Prx1⁺ fibroblasts as a previously unrecognized etiologic factor that may contribute to the pathogenesis of AD and suggest that targeting CCL11 may be a way to treat AD-like skin lesions.

Model-based meta-analysis to optimise S. aureus-targeted therapies for atopic dermatitis

Several clinical trials of Staphylococcus aureus (S. aureus)‒targeted therapies for atopic dermatitis (AD) have shown conflicting results about whether they improve AD severity scores. This study performs a model-based meta-analysis to investigate the possible causes of these conflicting results and suggests how to improve the efficacies of S. aureus‒targeted therapies. We developed a mathematical model that describes systems-level AD pathogenesis involving dynamic interactions between S. aureus and coagulase-negative Staphylococcus (CoNS). Our model simulation reproduced the clinically observed detrimental effects of the application of S. hominis A9 and flucloxacillin on AD severity and showed that these effects disappeared if the bactericidal activity against CoNS was removed. A hypothetical (modeled) eradication of S. aureus by 3.0 log₁₀ colony-forming unit per cm² without killing CoNS achieved Eczema Area and Severity Index 75 comparable with that of dupilumab. This efficacy was potentiated if dupilumab was administered in conjunction with S. aureus eradication (Eczema Area and Severity Index 75 at week 16) (S. aureus eradication: 66.7%, dupilumab 61.6% and combination 87.8%). The improved efficacy was also seen for virtual dupilumab poor responders. Our model simulation suggests that killing CoNS worsens AD severity and that S. aureus‒specific eradication without killing CoNS could be effective for patients with AD, including dupilumab poor responders. This study will contribute to designing promising S. aureus‒targeted therapy.

Use of bleach baths for atopic dermatitis: An Indian perspective

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disorder affecting 15–20% of children and 1–10% of adults. Staphylococcus aureus (S. aureus) infection is the most frequent complication of AD and is involved in the worsening of the disease. Systemic and topical antibiotics are used in the treatment for AD but there are concerns over increasing resistance. Bleach (sodium hypochlorite, NaOCl) baths are an inexpensive, widely accessible, alternative antibiotic treatment that may not worsen antibiotic resistance. Bleach baths are used as adjunctive treatment in AD patients to treat superinfections, although their mechanism of action is not well understood. Balancing safety concerns with efficacious treatment should be important especially for AD where the majority of patients are in pediatrics age groups. Studies available in PubMed databases were included in this review. Most suggested bleach bath improves clinical symptoms of AD and restores surface microbiome by eradicating bacteria, most notably S. aureus. Some studies have noted that this antimicrobial effect has reduced the need for topical corticosteroids. In addition, bleach seems to have strong anti-inflammatory and antipruritic effects. Overall, bleach baths seem to be safe on human skin, without disrupting the epidermal barrier function. The review concluded, although there are some advantages of use of bleach baths, more studies to investigate long-term efficacy and safety of bleach baths are required before fixing its role in the treatment of AD especially in the context of the Indian scenario.

miR-24-3p obstructs the proliferation and migration of HSFs after thermal injury by targeting PPAR-β and positively regulated by NF-κB

Thermal injury repair is a complex process during which the maintenance of the proliferation and migration of human skin fibroblasts (HSFs) exert a crucial role. MicroRNAs have been proven to exert an essential function in repairing skin burns. This study delves into the regulatory effects of miR-24-3p on the migration and proliferation of HSFs that have sustained a thermal injury; thereby, providing deeper insight into thermal injury repair pathogenesis. The PPAR-β protein expression level progressively increased in a time-dependent manner on the 12^th , 24^th , and 48^th hour following the thermal injury of the HSFs. The knockdown of PPAR-β markedly suppressed the proliferation of and migration of HSF. Following thermal injury, the knockdown also promoted the inflammatory cytokine IL-6, TNF-, PTGS-2, and P65 expression. PPAR-β contrastingly exhibited an opposite trend. A targeted relationship between PPAR-β and miR-24-3p was predicted and verified. miR-24-3p inhibited thermal injured-HSFs proliferation and migration and facilitated inflammatory cytokine expression through the regulation of PPAR-β. p65 directly targeted the transcriptional precursor of miR-24 and promoted miR-24 expression. A negative correlation between miR-24-3p expression level and PPAR-β expression level in rats burnt dermal tissues was observed. Our findings reveal that miR-24-3p is conducive to rehabilitating the denatured dermis, which may be beneficial in providing effective therapy of skin burns.

The Skin Microbiome of Patients With Atopic Dermatitis Normalizes Gradually During Treatment

Background

Atopic dermatitis (AD) is characterized by an altered skin microbiome dominantly colonized by S. aureus. Standard treatment includes emollients, anti-inflammatory medications and antiseptics.

Objectives

To characterize changes in the skin microbiome during treatment for AD.

Methods

The skin microbiomes of children with moderate-to-severe AD and healthy children were investigated in a longitudinal prospective study. Patients with AD were randomized to receive either standard treatment with emollients and topical corticosteroids or standard treatment with the addition of dilute bleach baths (DBB) and sampled at four visits over a three-month period. At each visit, severity of AD was measured, swabs were taken from four body sites and the composition of the microbiome at those sites was assessed using 16S rRNA amplification.

Results

We included 14 healthy controls and 28 patients. We found high relative abundances of S. aureus in patients, which correlated with AD severity and reduced apparent alpha diversity. As disease severity improved with treatment, the abundance of S. aureus decreased, gradually becoming more similar to the microbiomes of healthy controls. After treatment, patients who received DBB had a significantly lower abundance of S. aureus than those who received only standard treatment.

Conclusions

There are clear differences in the skin microbiome of healthy controls and AD patients that diminish with treatment. After three months, the addition of DBB to standard treatment had significantly decreased the S. aureus burden, supporting its use as a therapeutic option. Further study in double-blinded trials is needed.

Topical hypochlorous acid (HOCl) blocks inflammatory gene expression and tumorigenic progression in UV-exposed SKH-1 high risk mouse skin

Hypochlorous acid (HOCl) is the active oxidizing principle underlying drinking water disinfection, also delivered by numerous skin disinfectants and released by standard swimming pool chemicals used on a global scale, a topic of particular relevance in the context of the ongoing COVID-19 pandemic. However, the cutaneous consequences of human exposure to HOCl remain largely unknown, posing a major public health concern. Here, for the first time, we have profiled the HOCl-induced stress response in reconstructed human epidermis and SKH-1 hairless mouse skin. In addition, we have investigated the molecular consequences of solar simulated ultraviolet (UV) radiation and HOCl combinations, a procedure mimicking co-exposure experienced for example by recreational swimmers exposed to both HOCl (pool disinfectant) and UV (solar radiation). First, gene expression elicited by acute topical HOCl exposure was profiled in organotypic human reconstructed epidermis. Next, co-exposure studies (combining topical HOCl and UV) performed in SKH-1 hairless mouse skin revealed that the HOCl-induced cutaneous stress response blocks redox and inflammatory gene expression elicited by subsequent acute UV exposure (Nos2, Ptgs2, Hmox1, Srxn1), a finding consistent with emerging clinical evidence in support of a therapeutic role of topical HOCl formulations for the suppression of inflammatory skin conditions (e.g. atopic dermatitis, psoriasis). Likewise, in AP-1 transgenic SKH-1 luciferase-reporter mice, topical HOCl suppressed UV-induced inflammatory signaling assessed by bioluminescent imaging and gene expression analysis. In the SKH-1 high-risk mouse model of UV-induced human keratinocytic skin cancer, topical HOCl blocked tumorigenic progression and inflammatory gene expression (Ptgs2, Il19, Tlr4), confirmed by immunohistochemical analysis including 3-chloro-tyrosine-epitopes. These data illuminate the molecular consequences of HOCl-exposure in cutaneous organotypic and murine models assessing inflammatory gene expression and modulation of UV-induced carcinogenesis. If translatable to human skin these observations provide novel insights on molecular consequences of chlorination stress relevant to environmental exposure and therapeutic intervention.

Update on the Pathogenesis and Therapy of Atopic Dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disorder characterized by recurrent eczematous lesions and intense itch. Although it most often starts in infancy and affects children, it is also highly prevalent in adults. In this article, the main aspects of AD have been updated, with a focus on the pathogenetic and therapeutic aspects. The pathogenesis of AD is complex, and it is evident that a strong genetic predisposition, epidermal dysfunction, skin microbiome abnormalities, immune dysregulation, and the neuroimmune system are critical in AD development. Mutations in the genes associated with disrupted epidermal barrier, exaggerated pathological inflammation and inadequate antimicrobial peptides can promote enhanced Th2 inflammation and mediate pruritus. Current understanding of etiology highlights gut microbial diversity, NK cell deficiency, and different immunological phenotype with age and race. For topical anti-inflammatory treatment for mild-to-severe AD, phosphodiesterase 4 inhibitors (PDE-4), JAK inhibitors, and microbiome transplantation with Roseomonas mucosa provided more management selections. The treatment of moderate-to-severe AD has been limited to merely symptomatic and relatively nonspecific immunosuppressive approaches. In-depth understanding of the pathogenesis of AD has led to the development of innovative and targeted therapies, such as biologic agents targeting interleukin (IL)-4, IL-13 and JAK/STAT inhibitors. Other potential therapeutic agents for AD include agents targeting the T helper (Th) 22 and Th17/IL23 pathway. Antipruritic therapy and complementary probiotics therapy have also been reviewed.

Role of NF-κB in Ageing and Age-Related Diseases: Lessons from Genetically Modified Mouse Models

Ageing is a complex process, induced by multifaceted interaction of genetic, epigenetic, and environmental factors. It is manifested by a decline in the physiological functions of organisms and associated to the development of age-related chronic diseases and cancer development. It is considered that ageing follows a strictly-regulated program, in which some signaling pathways critically contribute to the establishment and maintenance of the aged state. Chronic inflammation is a major mechanism that promotes the biological ageing process and comorbidity, with the transcription factor NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) as a crucial mediator of inflammatory responses. This, together with the finding that the activation or inhibition of NF-κB can induce or reverse respectively the main features of aged organisms, has brought it under consideration as a key transcription factor that acts as a driver of ageing. In this review, we focused on the data obtained entirely through the generation of knockout and transgenic mouse models of either protein involved in the NF-κB signaling pathway that have provided relevant information about the intricate processes or molecular mechanisms that control ageing. We have reviewed the relationship of NF-κB and premature ageing; the development of cancer associated with ageing and the implication of NF-κB activation in the development of age-related diseases, some of which greatly increase the risk of developing cancer.

Advances in the Translational Science of Dermatitis

The cycle of converting mechanistic insight into therapeutic interventions is called translational science. It has been relatively sluggish in atopic dermatitis (AD), but finally pathomechanisms have been identified and therapeutic targets selected and refined. From inflammatory mediators, skin barrier enhancement, itch relief, and alteration of the microbiota, several therapies have been proposed and are actively being studied for AD, suggesting an end to the drought of innovation.

Myeloid cell-derived HOCl is a paracrine effector that trans-inhibits IKK/NF-κB in melanoma cells and limits early tumor progression

The myeloperoxidase (MPO) system of myeloid-derived cells (MDCs) is central to cellular innate immunity. Upon MDC activation, MPO is secreted into phagosomes where it catalyzes the production of hypochlorous acid (HOCl), a potent chlorinating oxidant. Here, we demonstrated that the myeloid lineage-restricted MPO-HOCl system had antitumor effects in early melanoma growth in aged mice. Orthotopic melanomas grew more slowly in immunocompetent MPO^+/+ host mice compared to age-matched syngeneic MPO^-/- mice. Real-time intravital tumor imaging in vivo and in cell cocultures revealed a cell-cell proximity-dependent association between MDC-derived MPO enzyme activity and blockade of ligand-induced IκBα degradation in tumor cells. HOCl directly trans-inhibited IκB kinase (IKK) activity in tumor cells, thereby decreasing nuclear factor κB (NF-κB) transcriptional activation and inducing changes in the expression of genes involved in metabolic pathways, cell cycle progression, and DNA replication. By contrast, HOCl induced transcriptional changes in CD8⁺ T cells related to ion transport and the MAPK and PI3K-AKT signaling pathways that are associated with T cell activation. MPO increased the circulating concentrations of the myeloid cell-attracting cytokines CXCL1 and CXCL5, enhanced local infiltration by CD8⁺ cytotoxic T cells, and decreased tumor growth. Overall, these data reveal a role for MDC-derived HOCl as a small-molecule paracrine signaling factor that trans-inhibits IKK in melanoma tumor cells, mediating antitumor responses during early tumor progression.

Long-term every-other-day administration of DMAMCL has little effect on aging and age-associated physiological decline in mice

The activation of transcription factor NF-κB is currently identified as one of the driving forces to the aging process. Genetic impairment of NF-κB signaling pathway or pharmacological inhibition of NF-κB activity has been shown to extend healthspan and lifespan in animal models, and delay or reduce many age-related symptoms. However, the aging intervention strategies based on NF-κB inhibition by the suitable small molecular compound is currently still lacking. The water-soluble dimethylaminomicheliolide (DMAMCL), can inhibit NF-κB activity and is currently undergoing clinical trials. In this study, we showed that 15 months of DMAMCL administration started in 1-year old male mice was well-tolerated and safe, and improved or had little effect on some age-associated symptoms, such as neurobehavioral phenotypes, physical performance, cardiac function, hematological parameters, immune aging phenotypes, clinical chemistry parameters, and glucose homeostasis. At the molecular level, DMAMCL administration mitigated serum levels of several age-associated inflammatory cytokines, including IL-6, IL-1α, IL-1β, TNF-α, IFN-γ, and CXCL2, and inhibited NF-κB activity in several aged tissues. Collectively, our results indicate that current strategy of DMAMCL administration may has little effect on aging process in mice, and provide basic clues to further exploit the possibility of DMAMCL-based aging intervention to promote healthy aging.

Staphylococcus aureus in Atopic Dermatitis: Past, Present, and Future

: The role of Staphylococcus aureus (SA) in the pathogenesis and management in atopic dermatitis is rapidly evolving. The modern understanding of SA in atopic dermatitis now includes an expanded array of virulence factors, the interplay of clonal and temporal shifts in SA populations, and host factors such as filaggrin and natural moisturizing factor. New, emerging therapies that focus on long-term, targeted elimination of SA colonization are currently under investigation (Br J Dermatol 2017;17(1)63-71). Herein, we discuss and review the latest staphylococcal and microbiome-modifying therapies including topical antibiotics, topical natural oil fatty acids, anti-SA vaccines, microbial transplantation, vitamin D supplementation, dupilumab and proposed future investigative directions.

Topical Esomeprazole Mitigates Radiation-Induced Dermal Inflammation and Fibrosis

Radiation therapy is a mainstream strategy in the treatment of several cancer types that are surgically unresectable. Unfortunately, cancer patients often suffer from unintended consequences of radiotherapy, including the development of skin inflammation (dermatitis), which may progress to fibrosis. These morbid complications often require interruption of radiotherapy and threaten the relapse of underlying cancer. Current treatment options for radiation dermatitis are suboptimal and compel the need to develop safer, more effective therapies. In this study, we assessed the biophysical properties of topically-formulated esomeprazole (here referred to as dermaprazole) and performed proof-of-concept studies to evaluate its efficacy in vitro and in vivo. We found that dermaprazole induced nuclear translocation of erythroid 2-related factor 2 (Nrf2) and significantly upregulated heme oxygenase 1 (HO1) gene and protein expression in a 3D human skin model. Our animal study demonstrated that dermaprazole improved macroscopic appearance of the irradiated skin and accelerated healing of the wounds. Histopathology data corroborated the photographic evidence and confirmed that both prophylactically and therapeutically administered dermaprazole conferred potent anti-inflammatory and antifibrotic effects. Gene expression data showed that dermaprazole downregulated several pro-oxidant, pro-inflammatory and profibrotic genes. In conclusion, topical formulation of the FDA-approved drug esomeprazole is highly effective in attenuating dermal inflammation and fibrosis.

Sodium hypochlorite body wash in the management of Staphylococcus aureus-colonized moderate-to-severe atopic dermatitis in infants, children, and adolescents

OBJECTIVES

A cleansing body wash containing diluted sodium hypochlorite (0.006% NaOCl) was evaluated for management of moderate-to-severe Staphylococcus aureus-colonized, atopic dermatitis in children.

METHODS

A 6-week, prospective, open-label study was conducted with 50 evaluable participants (ages 6 months to 17 years) who had moderate-to-severe atopic dermatitis with S aureus skin colonization documented by culture. Participants were instructed to continue using their current medications while using the study product, 0.006% NaOCl body wash, once daily to affected areas for 6 weeks. Primary outcome measures were Investigator's Global Assessment, Eczema Area and Severity Index, and Body Surface Area scores. Secondary outcome measures were the Visual Analog Scale for pruritus, Family Dermatology Life Quality Index, and Patient Satisfaction Questionnaire for Problem Areas. A subject daily diary and a six-item subject questionnaire that provided information on preferences for bleach bath vs body wash were secondary outcome measures.

RESULTS

Daily use of the 0.006% NaOCl body wash led to improvement for all outcome measures comparing baseline to 2-week and to 6-week evaluations. Of the 50 skin S aureus-positive subjects, 32/50 (64%) were still positive at 2 weeks. A 36.5% decrease in subject's daily record of topical corticosteroid application at end of study compared to baseline was found. Participant surveys indicated preferences for the body wash over bleach baths.

CONCLUSIONS

Sodium hypochlorite (NaOCl) body wash improved all outcome measures for moderate-to-severe S aureus-colonized AD in infants, children, and adolescents. The limited reduction in S aureus further suggests that sodium hypochlorite has ameliorative effects other than antimicrobial actions.

Research Techniques Made Simple: Parabiosis to Elucidate Humoral Factors in Skin Biology

Circulating factors in the blood and lymph support critical functions of living tissues. Parabiosis refers to the condition in which two entire living animals are conjoined and share a single circulatory system. This surgically created animal model was inspired by naturally occurring pairs of conjoined twins. Parabiosis experiments testing whether humoral factors from one animal affect the other have been performed for more than 150 years and have led to advances in endocrinology, neurology, musculoskeletal biology, and dermatology. The development of high-throughput genomics and proteomics approaches permitted the identification of potential circulating factors and rekindled scientific interest in parabiosis studies. For example, this technique may be used to assess how circulating factors may affect skin homeostasis, skin differentiation, skin aging, wound healing, and, potentially, skin cancer.

Topical, systemic and biologic therapies in hidradenitis suppurativa: pathogenic insights by examining therapeutic mechanisms

Hidradenitis suppurativa (HS) is a chronic inflammatory disease of the skin, manifesting in chronic, recurrent painful pustules, nodules, boils and purulent draining abscesses. Our current understanding of the pathogenesis of the disease is incomplete. This review aims to identify available treatment options in HS and discuss the pharmacological mechanisms through which such agents function. Identifying common pathways may inform our understanding of the pathogenesis of HS as well as identify future therapeutic targets. The pharmacological mechanisms implicated in topical therapies, antibiotic, hormonal, systemic immunomodulatory and biologic therapies for HS are discussed. Significant differences exist between agents and implicated pathways in therapy for mild and severe disease. This is an expression of the possible dichotomy in inflammatory pathways (and treatment responses) in HS. Studies involving monoclonal antibodies provide the greatest insight into what these specific mechanisms may be. Their variable levels of clinical efficacy compared with placebo bolsters the suggestion that differential inflammatory pathways may be involved in different presentations and severity of disease. Nuclear factor kappa B (NF-κB), tumor necrosis factor (TNF)-α and other innate immune mechanisms are strongly represented in treatments which are effective in mild to moderate disease in the absence of scarring or draining fistulae, however complex feed-forward mechanisms in severe disease respond to interleukin (IL)-1 inhibition but are less likely to respond to innate immune inhibition (through NF-κB or TNF-α) alone. It is unclear whether IL-17 inhibition will parallel TNF-α or IL-1 inhibition in effect, however it is plausible that small molecule targets (Janus kinase1 and phosphodiesterase 4) may provide effective new strategies for treatment of HS.

Topical agents for the treatment of atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is perhaps the most common inflammatory skin disorder worldwide, with an increasing incidence in developed countries. The mainstay treatment for patients with AD is topical therapies, which are used not only by the mild patients but also by the moderate-to-severe patients, in conjunction with systemic treatment. While topical steroids and calcineurin antagonists are widely used, these are associated with long-term cutaneous adverse effects (AEs) or a black box warning, preventing their chronic use. Areas covered: The aim of this review is to provide a comprehensive overview of new and upcoming topical therapies currently in development and undergoing clinical trials, as well as their safety and efficacy profiles, and discuss current topicals used in the management of AD. Expert opinion: AD is a heterogeneous disease with complex pathophysiology. Treatments available to date for AD provide disease control; however, patients struggle to find an optimized therapeutic regimen they may use long term and without severe effects. Novel therapies are currently under investigation, with the hope of shifting the paradigm of AD management from symptom control to disease eradication.

Comparison of bleach, acetic acid, and other topical anti-infective treatments in pediatric atopic dermatitis: A retrospective cohort study on antibiotic exposure

BACKGROUND/OBJECTIVES

Skin infection is common in atopic dermatitis (AD), often necessitating treatment with systemic antibiotics. Topical adjunctive therapies such as dilute bleach baths are increasingly recommended, and topical dilute acetic acid (AA) has not been widely studied. The objective of this study was to evaluate whether various topical anti-infective bathing recommendations were associated with decreased systemic antibiotic exposure in pediatric AD, as well as evaluate topical anti-infective recommendations over time within our institution.

METHODS

Clinical data were extracted from charts of pediatric patients from 1/1/2000 to 12/31/2005 and 1/1/2009 to 12/31/2014 who visited outpatient dermatology clinics at Mayo Clinic, Rochester, a tertiary referral center. Recommendations for topical anti-infectives (dilute AA, dilute bleach, other, or none) at any time after patient had clinically proven or suspected AD superinfection were recorded as exposures to topical anti-infective. Primary outcome was the number of systemic antibiotic courses in a 1-year period.

RESULTS

Of 1111 patients with AD, 753 met inclusion criteria (303 in 2000-2005; 450 in 2009-2014). Of these, 351 (46.6%) had culture-proven or clinically suspected superinfection. Topical anti-infective recommendations increased between the time periods (23.3% to 79.2%; P < 0.001) and number of courses of systemic antibiotics decreased (1.9 per year vs 1.5 per year, P = 0.010). Number of systemic antibiotic courses did not differ between those who received bathing recommendations and those who did not, nor between different anti-infective groups (P = 0.398).

CONCLUSIONS

Practice behaviors have changed, and topical anti-infectives are now commonly recommended. Neither dilute AA nor bleach baths were associated with fewer subsequent exposures to systemic antibiotics in the treatment of pediatric AD.

Consensus-based European guidelines for treatment of atopic eczema (atopic dermatitis) in adults and children: part II

This guideline was developed as a joint interdisciplinary European project, including physicians from all relevant disciplines as well as patients. It is a consensus-based guideline, taking available evidence from other guidelines, systematic reviews and published studies into account. This second part of the guideline covers antimicrobial therapy, systemic treatment, allergen-specific immunotherapy, complementary medicine, psychosomatic counselling and educational interventions, whereas the first part covers methods, patient perspective, general measures and avoidance strategies, basic emollient treatment and bathing, dietary intervention, topical anti-inflammatory therapy, phototherapy and antipruritic therapy. Management of AE must consider the individual clinical variability of the disease. Systemic immunosuppressive treatment with cyclosporine, methotrexate, azathioprine and mycophenolic acid is established option for severe refractory cases, and widely available. Biologicals targeting the T helper 2 pathway such as dupilumab may be a safe and effective, disease-modifying alternative when available. Oral drugs such as JAK inhibitors and histamine 4 receptor antagonists are in development. Microbial colonization and superinfection may cause disease exacerbation and can require additional antimicrobial treatment. Allergen-specific immunotherapy with aeroallergens may be considered in selected cases. Psychosomatic counselling is recommended especially in stress-induced exacerbations. Therapeutic patient education ('Eczema school') is recommended for children and adult patients. General measures, basic emollient treatment, bathing, dietary intervention, topical anti-inflammatory therapy, phototherapy and antipruritic therapy have been addressed in the first part of the guideline.

Aging Suppresses Skin-Derived Circulating SDF1 to Promote Full-Thickness Tissue Regeneration

Physicians have observed that surgical wounds in the elderly heal with thinner scars than wounds in young patients. Understanding this phenomenon may reveal strategies for promoting scarless wound repair. We show that full-thickness skin wounds in aged but not young mice fully regenerate. Exposure of aged animals to blood from young mice by parabiosis counteracts this regenerative capacity. The secreted factor, stromal-derived factor 1 (SDF1), is expressed at higher levels in wounded skin of young mice. Genetic deletion of SDF1 in young skin enhanced tissue regeneration. In aged mice, enhancer of zeste homolog 2 (EZH2) and histone H3 lysine 27 trimethylation are recruited to the SDF1 promoter at higher levels, and pharmacologic inhibition of EZH2 restores SDF1 induction and prevents tissue regeneration. Similar age-dependent EZH2-mediated SDF1 suppression occurs in human skin. Our findings counter the current dogma that tissue function invariably declines with age and suggest new therapeutic strategies in regenerative medicine.

Periodontitis: facts, fallacies and the future

This volume of Periodontology 2000 represents the 25th anniversary of the Journal, and uses the occasion to assess important advancements in periodontology over the past quarter-century as well as the hurdles that remain. Periodontitis is defined by pathologic loss of the periodontal ligament and alveolar bone. The disease involves complex dynamic interactions among active herpesviruses, specific bacterial pathogens and destructive immune responses. Periodontal diagnostics is currently based on clinical rather than etiologic criteria, and provides limited therapeutic guidance. Periodontal causative treatment consists of scaling, antiseptic rinses and occasionally systemic antibiotics, and surgical intervention has been de-emphasized, except perhaps for the most advanced types of periodontitis. Plastic surgical therapy includes soft-tissue grafting to cover exposed root surfaces and bone grafting to provide support for implants. Dental implants are used to replace severely diseased or missing teeth, but implant overuse is of concern. The utility of laser treatment for periodontitis remains unresolved. Host modulation and risk-factor modification therapies may benefit select patient groups. Patient self-care is a critical part of periodontal health care, and twice-weekly oral rinsing with 0.10-0.25% sodium hypochlorite constitutes a valuable adjunct to conventional anti-plaque and anti-gingivitis treatments. A link between periodontal herpesviruses and systemic diseases is a strong biological plausibility. In summary, research during the past 25 years has significantly changed our concepts of periodontitis pathobiology and has produced more-effective and less-costly therapeutic options.

Topical Hypochlorite and Skin Acidification Improves Erythroderma of Omenn Syndrome

We describe a case of Omenn syndrome displaying exudative erythroderma and other characteristic features, including alopecia, absent B and naïve T cells, hyper immunoglobulin E levels, and eosinophilia. A pathogenic recombination-activating RAG1 homozygous genetic mutation confirmed the diagnosis. She required frequent antibiotics at both treatment and prophylactic doses, which alone did not control her erythroderma, but her high risk of infection precluded the use of systemic agents such as cyclosporine, which would further suppress her already severely compromised immune system. Thrice-weekly topical dilute hypochlorite compresses, combined with skin acidification with a low pH emollient, were initiated to control inflammation and for cutaneous bacterial prophylaxis. She demonstrated a marked improvement in her erythroderma within days after treatment initiation. Further improvement continued with the addition of systemic corticosteroids, with resolution of erythroderma after her first dose. This case reveals for the first time that dilute topical hypochlorite and skin pH restoration holds promise to control severe dermatitis associated with immunodeficiency and inflammatory syndromes with minimal side effects.

Lysosomes Support the Degradation, Signaling, and Mitochondrial Metabolism Necessary for Human Epidermal Differentiation

Keratinocytes undergo significant structural remodeling during epidermal differentiation, including a broad transformation of the proteome coupled with a reduction in total cellular biomass. This suggests that intracellular digestion of proteins and organelles is necessary for keratinocyte differentiation. Here, we use both genetic and pharmacologic approaches to demonstrate that autophagy and lysosomal functions are required for keratinocyte differentiation in organotypic human skin. Lysosomal activity was required for mechanistic target of rapamycin signaling and mitochondrial oxidative metabolism. In turn, mitochondrial reactive oxygen species, produced as a natural byproduct of oxidative phosphorylation, were necessary for keratinocyte differentiation. Finally, treatment with exogenous reactive oxygen species rescued the differentiation defect in lysosome-inhibited keratinocytes. These findings highlight a reciprocal relationship between lysosomes and mitochondria, in which lysosomes support mitochondrial metabolism and the associated production of mitochondrial reactive oxygen species. The mitochondrial reactive oxygen species released to the cytoplasm in suprabasal keratinocytes triggers autophagy and lysosome-mediated degradation necessary for epidermal differentiation. As defective lysosome-dependent autophagy is associated with common skin diseases including psoriasis and atopic dermatitis, a better understanding of the role of lysosomes in epidermal homeostasis may guide future therapeutic strategies.

Management of the cutaneous adverse effects of antimelanoma therapy

The advent of targeted therapy and immunotherapy has revolutionized the management of advanced melanoma. However, these novel therapies are associated with adverse effects (AEs), of which cutaneous toxicities are the most frequently observed. These cutaneous AEs can exert significant morbidity and impact on patient quality of life, hence the recognition and management of AEs is fundamental in preventing interruption or cessation of survival-prolonging treatments. Additionally, knowledge of these AEs are necessary in order for healthcare professionals to counsel patients when starting treatment and in the initiation of AE prophylaxis. The incidence and clinical presentation of the cutaneous toxicities of novel melanoma therapies will be discussed, and treatment guidelines provided.

Chlorinative stress in age-related diseases: a literature review

Aging is an agglomerate of biological long-lasting processes that result being inevitable. Main actors in this scenario are both long-term inflammation and oxidative stress. It has been proved that oxidative stress induce alteration in proteins and this fact itself is critically important in the pathophysiological mechanisms leading to diseases typical of aging. Among reactive species, chlorine ones such as hypochlorous acid (HOCl) are cytotoxic oxidants produced by activated neutrophils during chronic inflammation processes. HOCl can also cause damages by reacting with biological molecules. HOCl is generated by myeloperoxidase (MPO) and augmented serum levels of MPO have been described in acute and chronic inflammatory conditions in cardiovascular patients and has been implicated in many inflammatory diseases such as atherosclerosis, neurodegenerative conditions, and some cancers. Due to these data, we decided to conduct an up-to-date review evaluating chlorinative stress effects on every age-related disease linked; potential anti-oxidant countermeasures were also assessed. Results obtained associated HOCl generation to the aging processes and confirmed its connection with diseases like neurodegenerative and cardiovascular pathologies, atherosclerosis and cancer; chlorination was mainly linked to diseases where molecular (protein) alteration constitute the major suspected cause: i.e. inflammation, tissue lesions, DNA damages, apoptosis and oxidative stress itself. According data collected, a healthy lifestyle together with some dietary suggestion and/or the administration of nutracetical antioxidant integrators could balance the effects of chlorinative stress and, in some cases, slow down or prevent the onset of age-releated diseases.

Diluted sodium hypochlorite (bleach) in dogs: antiseptic efficacy, local tolerability and in vitro effect on skin barrier function and inflammation

BACKGROUND

Diluted sodium hypochlorite represents an inexpensive and widely available topical antiseptic, but there are no tolerability and efficacy data in veterinary dermatology.

OBJECTIVES

To determine the in vivo antibacterial effect and tolerability of topical diluted bleach application and to assess its in vitro effect on skin barrier lipids and anti-inflammatory properties on keratinocytes.

METHODS

Topical hypochlorite at 0.05% and tap water were applied to both sides of the thorax of four healthy dogs. The anti-inflammatory effect on canine keratinocytes was determined by real-time polymerase chain reaction; skin barrier integrity was assessed by evaluating stratum corneum lipid changes in canine stratified epidermal constructs.

RESULTS

The cell viability of primary keratinocytes treated with water and diluted hypochlorite at 0.005 and 0.01%, reduced the percentage of viable cells by 10%. The exposure of primary keratinocytes to 0.005% diluted hypochlorite significantly reduced the induction of inflammatory genes chemokine ligand-2 (CCL2; P = 0.015) and thymus and activation-regulated chemokine (TARC/CCL17, P = 0.032). There were no changes in skin lipid ceramide and nonceramide fractions in stratified epidermal constructs cultured for 17 days with 0.05% hypochlorite. Topical hypochlorite at 0.05% and tap water were well-tolerated without signs of skin irritation. Although a marked reduction in bacterial counts was seen within 20 min of diluted bleach application compared to the tap water control, this was only marginally significant (P = 0.06).

CONCLUSIONS AND CLINICAL IMPORTANCE

The results indicate that a topical diluted bleach solution, at either 0.05 or 0.005% hypochlorite concentrations, is a well-tolerated antiseptic that also exhibits anti-inflammatory properties.